DE69722815T2 - METHOD FOR PRODUCING MULTIPLE ALCOHOLS - Google Patents

Description

The present invention relates to a process for the production of polyvalent alcohols. To put it more precisely, that The present invention relates to the production of polyvalent Alcohols from aldehydes, produced by aldol reaction, and a subsequent Hydrogenation reaction of the aldehyde to alcohols.

Neopentyl glycol and other corresponding ones Alcohols are e.g. B. in the manufacture of various synthetic Resins such as acrylic resins, polyester resins, polyurethane resins, alkyd resins and polycarbonate resins, important intermediates. These alcohols are also used in the manufacture of plasticizers, synthetic Lubricants or surfactants Means used.

Neopentyl glycol and other corresponding ones Alcohols have become conventional made by two processes. One process uses formaldehyde and aldehyde with a strongly alkaline catalyst, e.g. B. sodium hydroxide, Potassium hydroxide or calcium hydroxide to form alcohol, z. B. neopentyl glycol, reacted. However, this has Process the disadvantage that large quantities be formed on the corresponding formate as a by-product. Consequently is the procedure for an economic process is unsuitable unless it becomes at the same time an economically provable use for the formate found.

In the other process the aldol reaction of formaldehyde and aldehyde in the presence of an amine catalyst, in particular Triethylamine. Neopentyl glycol is e.g. B. by reacting formaldehyde and isobutyraldehyde obtained in the presence of triethylamine, thereby hydroxypivaldehyde is formed as the main product. This can be further hydrogenated whereby the desired Neopentyl glycol is obtained as the end product.

As hydrogenation catalysts proposed many types of catalysts. U.S. Patent No. 4,250,337 beats as a catalyst copper chromite with barium as a promoter. In U.S. Patent No. 4,855 515, the catalyst used is a mixture of copper oxide and Copper chromite with manganese oxide as a promoter. In EP Patent No. 343475 a mixed catalyst made of platinum, There is ruthenium and tungsten.

Copper chromite is used e.g. B. in the EP publication 522368 used alone as a catalyst. According to this publication can be the amount of by-products that are formed in the aldol reaction be reduced in the hydrogenation by the hydrogenation in a suitable alcohol solvent carried out is, whereby the purity of the neopentyl glycol obtained as the final product elevated can be.

The procedures described above have various shortcomings. If triethylamine is used as the catalyst, that is triethylamine in solved State in the reaction mixture and thus also in the hydrogenation stage present, it may be harmful Side reactions catalyzed and the yield of the desired Reduced alcohol. Triethylamine is for many hydrogenation catalysts also a catalytic poison, which is the number of suitable catalysts, that can be used reduced. Moreover triethylamine partially decomposes in the hydrogenation step, which increases the catalyst consumption in the process. To the catalyst consumption to a minimum, must triethylamine after hydrogenation by distillation from the reaction mixture obtained separated and recycled to the hydrogenation and / or aldol reaction; this means an additional one Stage in a continuous process.

So it would be beneficial if the catalyst to belong to a different type would, which is not in liquid Form is present and thus in the reaction mixture, that of the hydrogenation supplied should not be included and could replace the triethylamine that currently represents the commonly used aldol catalyst. On this way the investment cost for the whole process can be reduced because of a separate stage for the Separation of triethylamine from the hydrogenation product is not necessary would.

In addition, at many types of catalysts are used in hydrogenation without the catalyst, caused by triethylamine, is poisoned and without a subsequent reduction of the conversion products and / or without the formation of by-products.

The idea of using ion exchange resins Using catalyst in the aldol reaction is an ancient invention. U.S. Patent No. 2,818,443 discloses a reaction of formaldehyde with an aliphatic Aldehyde containing at least two carbon atoms in the presence an anion exchange resin catalyst to form hydroxyaldehyde, which is further hydrogenated to the corresponding alcohol. In this Patent emphasizes that specifically suitable anion exchange resins are quaternary ammonium groups included, e.g. B. Resins by reacting a tertiary amine with a copolymer of chloromethylated styrene and divinylbenzene be preserved. These resins are strongly basic anion exchange resins. It is also possible, a weakly basic anion exchange resin as aldol catalyst to use that by reacting dimethylamine with a copolymer is obtained from chloromethylated styrene and divinylbenzene.

According to this patent, the separation of unreacted formaldehyde from the reaction mixture before Hydrogenation recommended. The separation is carried out by distillation under excess pressure or by steam stripping at atmospheric pressure. The Hydrogenation catalyst according to this Publication used is Raney nickel.

DE patent 26 53 096 suggests the use of cation exchange resins as a catalyst for the aldol reaction. The aldol reaction can be carried out in a suitable organic solvent, e.g. B. aliphatic alcohols. After the reaction, the cation exchange resin is removed by filtration and the unreacted aldehyde is separated by distillation.

Recommended hydrogenation catalysts according to this patent are hydrogenation catalysts containing nickel or cobalt, those of chromium, aluminum, magnesium, barium, zinc, manganese, thorium and / or copper was added.

US-2 818 443-A relates to the manufacture of polyhydroxy compounds by the reaction of formaldehyde with an aliphatic aldehyde, containing at least two carbon atoms. This reaction is in In the presence of an anion exchange resin. A type of one Resin is a weakly basic anion exchange resin, the tertiary amino groups contains. The reaction is carried out at a temperature between 15 and 50 ° C.

GB 1 143 417 B describes a method for the production of 2,2-dimethylpropanol-3-al-1, in which isobutyraldehyde and aqueous formaldehyde down over a basic ion exchange resin in carbonate form, which is in a pillar with a length to diameter ratio of more than 5: 1 and which is kept at a temperature of 85 ° to 100 ° C. becomes.

According to the invention, it was observed that by using weakly basic anion exchange resins with a tertiary amine -NR ₂ as a functional group as an aldol catalyst and by carrying out the hydrogenation of the aldol product in the presence of a solvent and a hydrogenation catalyst and at a temperature of 50 to 200 ° C., many advantages are achieved can, the earlier known methods are missing.

The aldol reaction can with good Yield and without a recognizable side reaction, especially without the formation of Esters become. The selectivity the procedure regarding of the desired one Alcohol is increased. The aldol product is directly into the hydrogenation stage without further separation stages guided. In the hydrogenation reaction there is no aldol catalyst, e.g. B. triethylamine, exists and thus its separation and recycling to that Aldol stage of the process is not necessary. In addition, it is possible in The hydrogenation stage catalyzed many types of catalysts without triethylamine Formation of by-products without product purification stages associated with it stand to use. The hydrogenation can be carried out under milder conditions, because the use of solvent significantly reduces the required temperature; this does it possible that in the hydrogenation stage reasonable low temperatures are used. Even temperatures below the melting point of the hydroxy aldehyde intermediate are possible. For example Hydroxypivaldehyde tends to decompose at 130 ° C. Even dangerous Side reactions take place as a result of the lower hydrogenation temperature from. The useful life of the hydrogenation catalyst is extended if the reaction mixture which is fed to the hydrogenation contains no triethylamine. Furthermore is the regeneration of the aldol catalyst in the process according to the invention simple.

To achieve these advantages, the present invention relates to a process for the preparation of polyvalent alcohols by hydrogenation of an aldehyde, the aldehyde by aldol reaction of an aldehyde which contains an α-hydrogen atom and has the formula R ₁ CHO, or the mixture of the aldehyde with a second another aldehyde with the formula R ₂ CHO, in which R _{1 is} selected from an alkyl having 1 to 12 carbon atoms, cycloalkyl, aryl and aralkyl having 1 to 14 carbon atoms and R _{2 is} selected from H, alkyl having 1 to 12 carbon atoms, cycloalkyl, Aryl and aralkyl having 1 to 14 carbon atoms is obtained and the aldol reaction is carried out in the presence of a weakly basic anion exchange resin which has a tertiary amine NR ₂ as a functional group and at a temperature of 60 to 80 ° C and the hydrogenation in Presence of a solvent and a hydrogenation catalyst is carried out.

Ion exchange resins are used in cation exchange resins, Anion exchange resins and amphoteric ion exchange resins are classified. Dependent on of acidity and alkalinity In the ionogenic group we speak of strongly or weakly acidic Cation exchange resins and strong or weakly basic anion exchange resins.

Anion exchange resins have since 1947, when the first resins of the gel type with functional groups of the amine type have been considerable developed. Resins of the macroporous Types were developed in 1957 and the first macroporous anion exchange resins were put on the market around 1960. Polyacrylamide as a matrix for weak anion exchange resin came later launched in the 80s.

As a result of product developments, the mechanical and thermal stability has been considerably improved from 1960 until now. These changes have increased the useful life. The resin quality was improved and the density of the functional groups increased. Modern weak anion exchange resins almost entirely contain -N (CH ₃ ) ₂ groups, while / during the 1960s weak anion exchange resins also contained a lot of strong -N (CH3) ₃ ⁺ groups. Weak anion exchange resins were probably considered useful in the commercial aldol reaction for these reasons.

If polymers are used as matrices for catalysts, the activity and selectivity of the catalytic support groups are strongly influenced by so-called "polymer effects". An interaction between the polymer matrix and the surroundings affects the properties of the resin and the reasons for this can be both physical and chemical in nature.

Resin matrices are either of the gel type or are macroporous. The scaffolding structure of a gel type resin is obtained as a gel from a polymerization. Gel type resins do not have permanent porosity; they swell to varying degrees in polar solvents that open up their structure. The Spaces between the cross bridges, the one with swelling solvent filled are, can are viewed as micropores. These spaces can contain solvents, but also semi-dissolved polymer segments contain. The mobility due to the high viscosities inside the micropores solutions limited.

Macroporous resins are permanent internal porosity and usually is a higher one Degree of crosslinking of the polymer required to breakdown to prevent the structure. Macroporosity leads to better material transfer inside the particles and thus often to a better reaction speed.

According to the invention it has been observed that both gel-like and macroporous weakly basic anion exchange resins can advantageously be used as catalysts in the aldol reaction. The weak anion exchange resins belong to the amine type. These include resins having functional groups as a tertiary amine (-NR2, where the R's are the same group or different groups, e.g., an alkyl or aryl group). Strong anion exchange resins with a functional group of the -NR ₃ ⁺ type cannot be used because of the low conversion of the starting aldehyde.

The resin matrix used can e.g. B. from condensation products of epichlorohydrin with amine or ammonia, phenolic resins, acrylic resins or styrene copolymers, e.g. B. chloromethylated Styrene-divinylbenzene copolymer, consist. Weak anion exchange resins are both anion exchange resins, in where the resin matrix belongs to the gel type and those in which the Resin matrix macroporous is suitable. In these resins, the polymer matrix is an epoxy, Acrylic, styrene or phenolic resin. The one used in polymer matrix Crosslinking agent is common Divinylbenzene.

The ionic shape of the resin is important. The ion form according to the invention must be OH ^- when the functional group is charged. Otherwise the functional group should be in the free base form. Other ion forms like Cl-seem to be ineffective.

Resins like these are mostly used for treatment of water used are on the market e.g. B. under the Trade names LEWATIT (manufacturer Bayer AG); DOWEX (manufacturer Dow Chemical); DIAION, NEKROLITH and RELITE (manufacturer Mitsubishi Chemical); PUROLITE (manufacturer Purolite); AMBERLITE, AMBERLYST and DOLITE (manufacturer Rohm and Haas); SERDOLIT (manufacturer Serva Heidelberg GmbH); IONAX (manufacturer Sybron Chemicals Inc.) and FINEX (Manufacturer Finex-FX, Oy).

In one embodiment of the invention, the first step in the process is the aldol reaction of an aldehyde containing an α-hydrogen atom in the presence of the weakly basic anion exchange resins. The aldehyde has the general formula R ₁ CHO, wherein R1 is selected from alcohol with 1 to 12 carbon atoms, cycloalkyl, aryl and aralkyl with 1 to 14 carbon atoms. The aldol reaction forms a reaction product mixture comprising or containing an aldol of the aldehyde, an unsaturated aldehyde derived from the dehydrogenation of the aldol, or mixtures thereof. The term "unsaturated aldehyde derived from the dehydration of the aldol" refers to the α, β-olefin aldehyde derived from the dehydration of the aldol produced in the reaction.

In a second embodiment of the invention, the first step in the process is the aldol reaction of aldehydes, which is a mixture of an aldehyde containing an α-hydrogen atom and defined above and a second other aldehyde having the general formula R ₂ CHO, wherein R2 is selected from H, alkyl of 1 to 12 carbon atoms, cycloalkyl, aryl and aralkyl of 1 to 14 carbon atoms, in the presence of weakly basic anion exchange resins.

Suitable starting aldehydes are e.g. B. at least one of the following: formaldehyde, etanal, propanal, Butanal, pentanal, 2-methylpropanal (isobutyraldehyde), 2-methylbutanal, 2-ethylpentanal, 2-ethylhexanal, 2-isopropylbutanal, 2-phenylpropanal, 2-cyclohexylpropanal, 2-phenylbutanal, 2,3-diphenylpropanal, cyclopentylaldehyde and cyclohexyl aldehyde.

In an advantageous embodiment the invention is the aldehyde containing an α-hydrogen atom, isobutyraldehyde and the second other aldehyde is formaldehyde. The term "formaldehyde" includes conventional ones Formaldehyde obtained as an aqueous solution and anhydrous forms of formaldehyde, e.g. B. paraformaldehyde and trioxane. More commercially available aqueous formaldehyde usually contains relative small amounts of methanol.

In the stage of the aldol reaction z. B. an aldehyde and formaldehyde with an anion exchange resin in a molar ratio from 15: 1 to 1:15, preferably 5: 1 to 1: 5. The reaction is carried out at a temperature of 60 to 80 ° C. The Upper limit for the temperature is determined by the thermal resistance of the anion exchange resin set. The aldol reaction can be carried out as a batch process or as Semi-batch process or preferably as a continuous process carried out become.

The catalyst can directly with the Starting substances can be mixed or by methods that prevent the movement of the catalyst particles at one point are held, these methods the present invention not restrict yourself. With regard to a continuous process, the latter is the latter Process advantageous because in such a case the reaction mixture, which is obtained after the aldol reaction, no aldol reaction catalyst contains. In the former case, the Catalyst by filtration or any other method the hydrogenation are separated from the reaction mixture.

solvent can in the stage of the aldol reaction in an amount of 0 to 50% by weight, preferably used in a range from 0 to 30% by weight. The solvent swells the resin catalyst during he aldol reaction and helps the reaction mixture as a single Maintain phase. solvent also have a washing effect as they contain impurities and residues can wash from the resin and thus increase the life of the resin. Suitable solvents include water and various alcohols and ketones, e.g. B. methanol, Ethanol, 1-propanol, isopropanol, 1-butanol and isobutanol and mixtures from that.

The ion form of the anion exchange resin is of great importance with regard to the catalytic activity. When anion exchange resins are used as the aldol reaction catalyst, the ion form of the resin is unfavorable in the continuous use. Aldehydes as starting materials are easily oxidized to the corresponding carboxylic acids and carboxylic acids can also form reaction products. An ion exchange reaction takes place between carboxylic acids (RCOOH) and the functional group -NR2 of the resin, which is in the form of a free base: NR ₂ + RCOOH → NR ₂ HRCOO if the functional group is the form NR ₂ HRCOO, it is no longer catalytically active. The resin can be easily regenerated back to the -NR ₂ form by periodically with alkaline solutions, e.g. B. NaOH solution, washed or rinsed.

After the stage of the aldol reaction and, if necessary, after separation of the anion exchange resin the reaction mixture is directly hydrogenated without other stages fed. In the hydrogenation it is possible as a catalyst, preferably copper chromide, metals or metal oxides, selected made of copper, cobalt, chrome, manganese, nickel and zinc or mixtures of using it. It is also possible to use barium or magnesium to use. Platinum, ruthenium, Rhodium, palladium or tungsten or mixtures thereof are also possible. It is also advantageous to use these metals in combination with a suitable carrier, e.g. B. carbon, silicon dioxide, aluminum oxide or zeolites or Mixtures of using them.

The hydrogenation is in solvents carried out, which include alcohols, ketones and ethers, e.g. B. methanol, ethanol, Propanol, isobutanol, hexanol, octanol, neopentyl glycol and butyl ether or dioxane. Favorable solvents are methanol, propanol and isobutanol. The amount of solvent can range from 1 to 70% by weight, preferably between 10 and 50% by weight. The main role of the solvent is there in reducing the speed of side reactions and the application of a hydrogenation temperature below the melting point of hydroxyaldehyde to allow by dissolving the solid hydroxy aldehyde in the liquid phase.

The hydrogenation is preferred with increased Temperature and elevated Printing done. The temperature can range from 50 to 200 ° C, preferably 70 to 120 ° C and the hydrogenation pressure can be between 1 and 200 bar, preferably are between 5 and 100 bar. Fixed bed catalysts are preferred used. The hydrogenation can be carried out as a batch process or semi-batch process, preferably be carried out as a continuous process.

After the hydrogenation reaction the desired one Alcohol, e.g. B. pentaerythritol, neopentyl glycol or trimethylol propane, by a suitable method, e.g. B. by distillation from the Reaction mixture removed and the solvents used can Hydrogenation and / or aldol reaction stage are fed back.

The invention will be described in more detail below based on the attached Examples explained.

EXAMPLE 1

Hydroxypivaldehyde was used a weak anion exchange resin (IRA 67) as a catalyst in a continuous tube reactor manufactured.

The experimental arrangements were as follows: Reactor: Tube reactor (glass), length 1 = 70 cm, diameter d = 1.6 cm with cooling jacket Catalyst: Amberlite IRA 67, volume V = 130 ml Feed: Mixture of formalin and IBAL in methanol, methanol content 12% by weight molar ratio IBAL / FA: 1.05 Temperature: 60 ° C Print: 1 bar dwell time: 7 h Operation mode: The feed mixture is continuously pumped through the resin bed, which is kept at a constant temperature; Feed rate 18.6 ml / h

The analyzed composition of the Product mixture, 200 g, is given in Table 1 below.

TABLE 1

"Other" includes unidentified Components.

The following selectivity, conversion and yield values can be calculated based on formaldehyde, which is the limiting component. HPA selectivity: 99.0% based on converted formaldehyde HPA yield: 94.8%, based on formaldehyde FA conversion: 95.8%

EXAMPLE 2a

An aldol reaction of formaldehyde and IBAL was carried out by the procedure of Example 1. The Catalyst was separated by filtration and methanol was mixed with the solution in an amount of 51% by weight. The hydrogenation was carried out, adding 160 g of the above solution into a batch-type Parr reactor with a volume of 300 ml introduced were maintained and a constant hydrogen pressure of 70 bar was maintained has been. The hydrogenation temperature was 140 ° C and the time was 120 minutes. The hydrogenation catalyst was copper chromite on alumina, the total Cu content was 34% by weight, the Cr content was 32% by weight. The amount of catalyst was 5.0% by weight based on the amount of HPA.

EXAMPLE 2b (comparison)

In this example, the same experimental setup as in Example 2 was used. The difference was the feed mixture containing TEA (triethylamine) as a catalyst for the aldol reaction. The Working conditions were the same as in Example 2.

The composition of the feed and product mixtures in both examples are in the following table 2 specified. The NPG yield is expressed as the percentage of NPG set in the hydrogenation of the amount of HPA present in the feed stream specified. The NPG selectivity is the percentage of NPG formed during hydrogenation of the implemented HPA. The conversion of HPA is as that percentage of the converted HPA in the amount of HPA, which in the feed is present.

TABLE 2

In Example 2a, the NPG selectivity was 90.7% and the HPA conversion was 98.1 o. In Comparative Example 2b the corresponding values were 87.7% and 97.0%.

The results indicate that a higher NPG selectivity and thus better utilization of raw materials is achieved when ion exchange resin as an aldol reaction catalyst in the process for the production of NPG is used.

EXAMPLE 3

61.83 g formaldehyde and 75.01 g isobutyraldehyde were implemented by the method according to Example 1. The catalyst was 41.61 g AMBERLITE IRA-93, which is a macroporous weak anion exchange resin is. The reaction temperature was 60 ° C and IBAL was in the course added by 1.4 hours. The results are in the table below 3 specified.

TABLE 3

The IBAL conversion (2 hours after IBAL addition) was 68.5% and the HPA selectivity was 100.0%.

The aldol reaction also works with another type of resin (IRA-93), although the reaction mixture is lower than with acrylamide resin IRA-68.

EXAMPLE 4

Aldol reaction tests were carried out in a tubular reactor using weak and strong anion exchange resins as the catalyst, the residence time was 1.5 hours, the temperature was 60 ° C and the molar ratio IBAL / CH ₂ O was 1: 1. The matrix of both resins was a gel type polystyrene crosslinked with divinylbenzene. The weak anion exchange resin was Diaion WA10 (Mitsubishi Chemical Corp.), the functional groups of which were the -N (CH ₃ ) ₂ type. The strong anion exchange resin was Amberlite IRA-400 (Rhom and Haas Company), its functional groups belonged to the -N (CH ₃ ) ₃ ⁺ type. The ion form of both resins was OH ^- . After the reaction time of 6 hours, a product sample was taken for analysis.

The results are as follows Table 4 given.

TABLE 4

The results shown in Table 4 show that it is advantageous to use a weakly basic anion exchange resin which has a tertiary amine -NR2 as a functional group instead of a strongly basic anion exchange resin which has a group -NR ₃ ⁺ as a functional group. Weak anion exchange resins which have a primary group —NH ₂ or a secondary group —NHR cannot be used either, since they are quickly inactivated under synthesis conditions.

EXAMPLE 5

Tests of the aldol reaction were carried out in a tubular reactor using a weak anion exchange resin as catalyst, the residence time was 2 hours, the temperature was 60 ° C and the molar ratio IBAL / CH ₂ O was 1: 1. All resins were weakly basic anion exchange resins with a functional group -N (CH ₃ ) ₂ . Several matrices were used: polyacrylamide, crosslinked with divinylbenzene (Amberblite IRA-67, Rohm and Haas Company), polystyrene, crosslinked with divinylbenzene (Abmerlite IRA-96, Rohm and Haas Company), epoxy resin (Dovex WGR-2, Dow Chemical Co ) and phenol-formaldehyde resin (Duolite A-7, Rohm and Haas Company). The ion form in all resins was OH ^- . After a reaction time of 6 hours, a product sample was taken for analysis.

The results are as follows Table 5 given.

TABLE 5

A weak one is particularly advantageous Anion exchange resin, which is a matrix of polyacrylic resin, which with Divinylbenzene is crosslinked.

EXAMPLE 6

Tests of the aldol reaction were carried out in a tubular reactor using a weak and strong anion exchange resin as a catalyst, the residence time was 2 hours, the temperature was 60 ° C. and the molar ratio IBAL / CH ₂ O was 1: 1. The anion exchange resin was Amberlite IRA-67, the functional groups of which were -N (CH3) 2 groups; the matrix polyacrylamide resin was cross-linked with divinylbenzene. The ionic form of the resins were free base and Cl ^- .

The results are shown in Table 6.

TABLE 6

It is advantageous to use anion exchange resin in the aldol reaction which has the ion form of a free base or OH instead of Cl ^- . Anion exchange resins with a different ion form have no effect on the aldol reaction.

EXAMPLE 7

The aldol reaction was carried out as in Example 6, but two different weak anion exchange resins with the functional group -N (CH ₃ ) _{2 were used} as the catalyst. The matrices were of the gel type (AMBERLITE IRA-67, Rohm and Haas Company) and of the macroporous type (PUROLITE A835, The Purolite Company).

The results are in Table 7 below specified.

TABLE 7

The made from the material Resins can dependent on vary by the nature of the matrix.

EXAMPLE 8

Propionaldehyde and formaldehyde were used in water-methanol solution with Ion exchange resin IRA 67 implemented as a catalyst. formaldehyde was used in excess (20 to 25% over the stoichiometric Quantity). The initial temperature was 50 ° C and increased by approximately during the reaction 10 ° C during the Reaction around 10 ° C. The results are shown in Table 8 below.

TABLE 8

The results show that minor Amounts of methanol lower the propionaldehyde conversion, the selectivity for dimethylolpropionaldehyde but do not interfere. EXAMPLE 9 Propionaldehyde and formaldehyde were in water-alcohol solution with ion exchange resin IRA 67 implemented as a catalyst. Formaldehyde was in excess (25% above the stoichiometric Amount) used. The initial temperature was 50 ° C and it increased during the Reaction around 6 ° C. The results are shown in Table 9 below.

TABLE 9

The results show that when methanol is replaced by isopropanol, a higher conversion and a higher selectivity become.

EXAMPLE 10

The aldol reaction was carried out in a glass reactor with a total volume of 0.8 dm ³ . The reactor was equipped with a stirrer which had a rotation speed of 500 min ^-1 . The heating of the reactor was carried out using a thermostatically controlled water jacket and the temperature was kept constant during the reaction.

The starting substances 2-ethylhexanal (2-EHAL) and formaldehyde (37 o) were added to the reactor and allowed to reach the reaction temperature while the mixture was stirred. The reaction was started by entering the ion exchange catalyst started in the reactor. When the reaction samples have been taken was stirring stopped, the phases were allowed to separate for 1 minute, it was a sample is taken from the organic phase. The mass of organic Phase was weighed after an experimental run. The molar ratio of 2-EHAL to formaldehyde was 1: 1.5 in all runs. The conditions are given in Table 10a and the composition of the organic Phase after an 8 hour run is given in Table 10b.

TABLE 10a

TABLE 10b

EXAMPLE 11

The effect of the amount of solvent on the selectivity of hydrogenation from HPA to NPG was investigated in this example. The crude HPA was made using a weak anion exchange resin as a catalyst for the aldol reaction. The experimental arrangements are given below: Reactor: 300 ml Parr with a rotating catalyst basket Catalyst: Ni on silicon dioxide, total Ni content 73% by weight (Ni, NiO) Feed: Raw HPA from the aldol reaction without purification, batch total 160 g Solvent: methanol Catalyst / HPA-ratio: Constant 5.5% by weight of catalyst, based on the amount of HPA Temperature: 100 ° C Print: 70 bar (abs) Reaction time: 120 min Amount of solvent: 0, 20, 40% by weight based on the hydrogenation feed mixture Operation mode: Batch process that the Keeps hydrogen pressure constant.

The given in Table 11 below Results show that the Effect of the solvent (methanol) on selectivity for NPG increases when the amount of solvent Methanol increases:

TABLE 11

The increasing amount of solvent Methanol also slowed the by-product formation rates HPHP and NPG monoisobutyrate, which increases the overall selectivity of the hydrogenation increased from HPA to NPG.

EXAMPLE 12

The applicability of other solvents, which are to be used in the hydrogenation of HPA in NPG has been described in examined this example. Isobutanol was used as a solvent used in the hydrogenation.

The experimental arrangement is given below: Reactor: 300 ml Parr with a rotating catalyst basket Catalyst: Ni on silicon dioxide, total Ni content 69% by weight (Ni, NiO), Cr content 13% by weight Feed: Raw HPA from the aldol reaction without any purification, total batch 160 g Solvent: Main solvent: isobutanol, 7% by weight MeOH also present in the mixture Catalyst / HPA-ratio: Constant 5.5% by weight of catalyst, based on the amount of HPA Temperature: 100 ° C Print: 70 bar (abs) Reaction time: 180 min Amount of solvent: iBUOH and MeOH, a total of 50 wt .-% in the reaction mixture Operation mode: Batch process that keeps the hydrogen pressure constant.

The composition of the feed and the product mixtures are given in Table 12.

TABLE 12

NPG selectivity was 98.3% and the HPA conversion was 99.7 o.

The result shows that isobutane a suitable solvent for use in hydrogenation.

EXAMPLE 13

Weak anion exchange resin (Abmerlite IRA 67, manufactured by Rohm & Haas) was used as a catalyst in the aldol reaction to produce hydroxypivaldehyde from formaldehyde and isobutyraldehyde. Methanol was in the reaction mixture added to a feed for hydrogenation which had the properties given in Table 13a:

TABLE 13a

The following hydrogenation catalysts were tested. NPG selectivity, NPG yield and HPA conversion were calculated to compare the performance of each catalyst. NPG-yield: Catalyst 1: Ni on silicon dioxide, total Ni content 73% by weight Catalyst 2: Ni on silicon dioxide, total Ni content 78% by weight Catalyst 3: Ni on silicon dioxide, MgO-supported, total Ni content 74% by weight Catalyst 4: Ni on silicon dioxide, total Ni content 78% by weight Catalyst 5: Ni (69% by weight) / Cr (13% by weight) on silica, Catalyst 6: CuCr on aluminum oxide, Ba-supported, total Cu 34% by weight, Cr 32% by weight Catalyst 7: CuZn on aluminum oxide, Cu 25% by weight, Zn 33.5% by weight Catalyst 8: Ni on aluminum oxide, Ni 20% by weight

All catalysts were crushed and a particle size of 1.0 sieved up to 1.4 mm. The hydrogenation was carried out in a Parr reactor a rotating basket and mixing trays. The catalyst was activated by one hour at 170 ° C, at a hydrogen pressure of 2 bar (abs.) were heated, with the exception of the catalysts 8, at which the activation temperature was 250 ° C. The hydrogenation pressure was 70 bar and the hydrogenation time was 180 minutes. The hydrogenation temperature was 100 ° C, except for the Catalysts 6 and 7 using 140 ° C.

The results are as follows Table 13b given.

TABLE 13b

The selectivity and conversion calculations are based on the analysis of the hydrogenation product mixture. For determination Liquid chromatography of FA, HPA, HPHP, HCOOH and HPAA was used, to determine IBAL, McOH, NPG and NPG isobutyrate Gas chromatography used.

The most selective catalyst to make of NPG with a high degree of conversion are the two Ni catalysts on silica carrier, Catalyst 3 and Catalyst 5. Also Catalyst 6 (CuCr on alumina) delivered reasonable good results at the higher Temperature (140 ° C), however, catalyst 8 (Ni on alumina) showed a poor one Activity, although a higher one Temperature (250 ° C) while activation of the catalyst was used.

EXAMPLE 14

Example 6 was repeated using a 1.5 hour residence time. From the outlet The reactor was sampled 8 hours and 72 hours after the start of the reaction. Then the resin was regenerated by introducing an aqueous solution of NaOH (1 M) through the resin bed. The reaction was started again and a sample was taken 8 hours after the start of the reaction. The results are shown in Table 14 below.

TABLE 14

The results indicate that the resin catalyst in a simple way to the original Condition can be regenerated.

EXAMPLE 15

The hydrogenation of HPA to NPG was investigated in methanol as a solvent. The experimental arrangements are as follows: Reactor: 300 ml Parr with rotating catalyst basket Catalyst: Ni on silicon dioxide, total Ni content 69% by weight (Ni, NiO), Cr content 13% by weight, 26.7 g Feed: Raw HPA from the aldol reaction without any purification, batch total 160 g Solvent: methanol Temperature: 70 ° C Print: 70 bar (abs) Reaction time: 240 min Operation mode: Batch process that keeps the hydrogen pressure constant.

The composition of the feed and product mixture is given in Table 15.

TABLE 15

NPG selectivity was 98.5% and the HPA conversion was 91% based on product analysis.

The results show that one use of solvent it possible makes to hydrogenate at low temperatures, the amount of by-products is very low.

Claims (18)

Process for the preparation of polyvalent alcohols by hydrogenation of an aldehyde, the hydrogenation being carried out in the presence of a solvent and a hydrogenation catalyst and the aldehyde being obtained by aldol reactions of an aldehyde in the presence of a weakly basic anion exchange resin, characterized in that the aldol reaction with an aldehyde is carried out with an α-hydrogen atom and with the formula R ₁ CHO or with a mixture of the aldehyde and a second other aldehyde with the formula R ₂ CHO, wherein R1 is selected from an alkyl having 1-12 carbon atoms, cycloalkyl, aryl and Aralkyl of 1-14 carbon atoms and R2 is selected from H, alkyl of 1-12 carbon atoms, cycloalkyl, aryl and aralkyl of 1-14 carbon atoms and that the aldol reaction is carried out at a temperature of 60-80 ° C that the aldol product obtained directly to a subsequent hydrogenation step without any and a previous separation of the unreacted aldehydes is supplied and that the hydrogenation is carried out at a temperature of 50-200 ° C, preferably 70-120 ° C and a pressure of 1-200 bar, preferably 5-100 bar and in which the weakly basic Anion exchange resin has a tertiary amine -NR2 as a functional group. A method according to claim 1, characterized in that the solvent is an aliphatic alcohol or ether. A method according to claim 2, characterized in that the solvent Methanol, ethanol, n-propanol, isopropanol, n-butanol or isobutanol or mixtures thereof. Method according to one of claims 1-3, characterized in that that the solvent in an amount of 1-70 % By weight, preferably 10-50 % By weight of the reaction mixture which is hydrogenated is used. Method according to one of the preceding claims, characterized characterized that the weakly basic anion exchange resin is an amine derivative of a chloromethylated styrene-divinylbenzene copolymer. Method according to one of claims 1-4, characterized in that that the weakly basic anion exchange resin is an amine derivative of a Acrylic polymer. Method according to one of claims 1-4, characterized in that that the weakly basic anion exchange resin is an amine derivative of a Is epoxy or phenolic resin. Method according to one of claims 1-7, characterized in that the solvent can also be used in the aldol reaction. A method according to claim 8, characterized in that the amount of solvent is at least 7% by weight. Method according to one of claims 1-9, characterized in that the aldehyde with an α-hydrogen atom butyraldehyde is. Method according to one of claims 1-10, characterized in that that the aldehyde with an α-hydrogen atom butyraldehyde and the second other aldehyde is formaldehyde. Method according to one of the preceding claims, characterized characterized in that the molar ratio of formaldehyde to aldehyde with an α-hydrogen 15: 1-1 : 15 is in the aldol reaction. Method according to one of the preceding claims, characterized characterized in that the one or more starting aldehydes selected are from the group consisting of formaldehyde, etanal, propanal, butanal, Pentanal, 2-methylpropanal (Isobutyraldehyde), 2-methylbutanal, 2-ethylpentanal, 2-ethylhexanal, 2-isopropylbutanal, 2-phenylpropanal, 2-cycolhexylpropanal, 2-phenylbutanal, 2,3-diphenylpropanal, cyclopentylaldehyde, Cyclohexyl aldehyde and mixtures thereof. Method according to one of the preceding claims, characterized characterized in that the aldehyde is a mixture of isobutyraldehyde and is formaldehyde and the end product is neopentyl glycol. Method according to one of the preceding claims, characterized characterized in that the hydrogenation catalyst metals or metal oxides, selected made of Cu, Co, Cr, Mn, Zn and Ni or mixtures thereof or copper chromite contains. Method according to one of the preceding claims, characterized characterized in that the catalyst contains metals selected from Chromium, magnesium, barium or zinc and mixtures thereof. Method according to one of claims 1-14, characterized in that that the hydrogenation catalyst used is a catalyst, the platinum, ruthenium, palladium, rhodium, tungsten or mixtures of which includes. Method according to claims 15-17, characterized in that the hydrogenation catalyst contains an inert support material selected from Carbon, silica, alumina, zeolites or mixtures thereof.